Hub cap vent shield

ABSTRACT

A vent plug for a hub cap is provided. The vent plug includes a cover and base forming a chamber. A vent plug body extends from the base and forms a cavity. A shield is coupled to the vent plug body. The shield comprises an annularly extending disc that traverses the cavity. The shield includes a connecting surface to connect the shield to the vent plug body. The shield provides a lubrication/liquid barrier to inhibit lubrication (or other liquid) from entering the cavity formed by the vent plug body and the chamber. The connection between the shield and the vent plug body allows a gas (typically air) to vent past the shield into the cavity and, when pressure is sufficiently high, to the chamber and eventually atmosphere.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication Ser. No. 62/629,266, filed Feb. 12, 2018, the disclosure ofwhich is incorporated herein as if set out in full.

BACKGROUND

Vehicles, and especially heavy-duty vehicles such as tractors andtrailers, have wheel ends assemblies that mount a rotating tire on anon-rotating axle or spindle. The wheel end assembly typically has amain body or hub that defines a cavity. The main body houses an inboardbearing, a fastening nut, and an outboard bearing assembly among otherthings.

The cavity of the main body contains a lubricant to facilitate operationof, for example, the bearings. The lubricant may be oil or grease. Themain body may be bounded, on the outboard side, with a sight window suchthat the level of the oil or grease may be viewed and monitored.Lubricant may be added as necessary depending on the level shown in theone or more sight windows.

During operation, the lubricant heats. The heat can induce an increasein pressure within the cavity. Thus, it is desirable to provide a vent(sometimes referred to as a vent path) to allow pressure equalizationbetween the cavity and the environment, which is typically theatmosphere.

Venting the wheel end assembly, however, has several drawbacks. One ofthe several drawbacks includes that the vent can provide a leak pathallowing oil to egress to the environment. The vent also provides a leakpath allowing foreign matter, such as, dirt, water, or the like, toingress to the cavity. The foreign matter can foul the lubricant andpotentially damage the parts of the wheel end assembly including, forexample, the bearings. The vent is typically about the outboard end capof the hub assembly and may be in a plug in the end cap where the plughas a vent path, sometimes referred to as a vent plug.

To inhibit ingress of foreign matter and egress of oil, the vent path,whether in a plug or not, may provide a labyrinth or tortuous pathbetween the cavity and the environment, or atmosphere. The vent may alsoinclude a diaphragm or valve that normally isolates the cavity from theatmosphere but places the cavity and atmosphere in fluid communicate(via the vent) when the pressure in the cavity exceeds a predefinedthreshold.

Improvements to the vent, however, are desirable. Thus, against thisbackground, an improved vent is provided.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary, and the foregoing Background, is not intendedto identify key aspects or essential aspects of the claimed subjectmatter. Moreover, this Summary is not intended for use as an aid indetermining the scope of the claimed subject matter.

In some aspects of the technology, a vent plug for a hub cap isprovided. The vent plug includes a cover and base forming a chamber. Avent plug body extends from the base and forms a cavity. The base has atleast an aperture to receive a valve. The valve selectively opens andcloses to place the cavity in fluid communication with the chamber. Ashield is coupled to the vent plug body. The shield comprises anannularly extending disc that traverses the cavity. The shield includesa connecting surface to connect the shield to the vent plug body. Theshield provides a lubrication/liquid barrier to inhibit lubrication (orother liquid) from entering the cavity formed by the vent plug body andthe chamber. The connection between the shield and the vent plug bodyallows a gas (typically air) to vent past the shield into the cavityand, when pressure is sufficiently high, to the chamber and eventuallyatmosphere.

These and other aspects of the present system and method will beapparent after consideration of the Detailed Description and Figuresherein.

DRAWINGS

Non-limiting and non-exhaustive embodiments of the present invention,including the preferred embodiment, are described with reference to thefollowing figures, wherein like reference numerals refer to like partsthroughout the various views unless otherwise specified.

FIG. 1 shows a perspective view of a hub cap consistent with thetechnology of the present application.

FIG. 2 shows a cross sectional view of the vent plug of FIG. 1consistent with the technology of the present application.

FIG. 3 shows a perspective view of a shield for the vent plug of FIG. 1consistent with the technology of the present application.

FIG. 4 shows a perspective view of a shield for the vent plug of FIG. 1consistent with the technology of the present application.

FIGS. 5A-5D show cross sectional views of exemplary vent plugs withshields consistent with the technology of the present application.

FIG. 6 shows a cross section of a detail for connecting a shield and avent plug body consistent with the technology of the presentapplication.

FIGS. 7A and 7B show cross sectional views of vent plug with shieldsconsistent with the technology of the present application.

FIG. 8 shows a cross section view of a detail for connecting a shieldand a vent plug body consistent with the technology of the presentapplication.

FIG. 9 shows a cross section of a vent plug with a shield consistentwith the technology of the present application.

FIG. 10 shows a cross section of a vent plug with a shield consistentwith the technology of the present application.

FIG. 11 shows a cross section of a vent plug with a shield consistentwith the technology of the present application.

DETAILED DESCRIPTION

The technology of the present application will now be described morefully below with reference to the accompanying figures, which form apart hereof and show, by way of illustration, specific exemplaryembodiments. These embodiments are disclosed in sufficient detail toenable those skilled in the art to practice the technology of thepresent application. However, embodiments may be implemented in manydifferent forms and should not be construed as being limited to theembodiments set forth herein. The following detailed description is,therefore, not to be taken in a limiting sense.

The technology of the present application is described with specificreference to a hub cap with a vent plug for a steer or trailer. However,the technology described herein may be used for other vehicles wheelends, such as, for example, tractors, cars, airplane landing gear, andthe like. The technology also can be used to vent drive axles. Moreover,the technology of the present application will be described withrelation to exemplary embodiments. The word “exemplary” is used hereinto mean “serving as an example, instance, or illustration.” Anyembodiment described herein as “exemplary” is not necessarily to beconstrued as preferred or advantageous over other embodiments.Additionally, unless specifically identified otherwise, all embodimentsdescribed herein should be considered exemplary.

A hub cap 10 is shown in FIG. 1. The hub cap 10 as shown is a hub capthat is currently available from Stemco Products, Inc. The hub cap 10 asshown has a generally cylindrical body 12 with an inboard side 14 and anoutboard side 16. The inboard side 14 has a flanged surface 18 having aplurality of bolt holes 20 to allow the hub cap 10 to be bolted to thewheel end. The outboard side 16 has a sight glass 22 and an end ring 24.The end ring 24 has bores 26 that receive fasteners 28 to couple the endring 24, sight glass 22, and seals 23 to the outboard side 16 of the hubcap 10. The fasteners may be rivets, screws, pins, or the like. In someembodiments, the end ring 24 and sight glass 22 may be integral with theoutboard side 16 of the hub cap 10, which would remove the need for thebores 26, fasteners 28, and seals.

The sight glass 22 and end ring 24 provide an aperture 30. A vent plug32 is provided in the aperture 30. The vent plug 32 has a cover 34 thatis coupled to a base 36. The junction of the cover 34 and base 36 is atan interface 38. As can be appreciated, the vent plug 32 is located atthe geometric center of the hub cap 10. In other embodiments, the ventplug 32 may be located off-center. In still other embodiments, aplurality of vent plugs may be provided at symmetrical or asymmetricallocations.

FIG. 2 shows a cross sectional view of the vent plug 32 in isolation.The vent plug has the cover 34 coupled to the base 36. The base 36 hasan outer edge surface 39 and a boarder wall 40 that form a shelf orledge. The outer edge surface 39 has a width W1. The boarder wall 40 hasan outer diameter D1. The cover 34 has a concave dome 42 and a rim 44 atthe outer edge 43 of the dome 42. The rim 44 has a width W2. The rim 44has an inner diameter D2 slightly smaller than the outer diameter D1such that a frictional engagement is maintained between the boarder wall40 and the rim 44 to hold the cover 34 to the base 36. However, as shownin FIG. 2, the inner diameter D2 of the rim 44 may be slightly stretchedto be greater than the outer diameter D1 when installed to form theinterference fit. An interface 38 between the cover 34 and the base 36is formed by the boarder wall 40, outer edge surface 39, and the rim 44.Notice, in certain aspects, the cover 34 and the base 36 may be a singleunit. If formed as a monolithic or single unit, the interface 38 may bereplaced with perforations or the like. While shown as a friction fit,the cover 34 and the base 36 could be coupled using other couplingtechniques such as, for example, welding (sonic or heat), adhering,gluing, curing, or the like.

The cover 34 and the base 36 define a chamber 46. The cover 34 has aplurality of ribs 48, defining concentric rings, that extend into thechamber 46 towards the base 36. The base 36 has a plurality of ribs 49,defining concentric rings, that extend into the chamber 46 towards thecover 34. The ribs 48 of the cover 34 and the ribs 49 of the base 36 aregenerally alternating and define a labyrinth path 50 between a centralaperture 52 in the base 36 and the interface 38. The labyrinth path 50provides a tortuous vent path that allows gas to travel relativelyfreely, but inhibits liquids from leaking through the path, whichinhibits the lubrication from exiting to the atmosphere. The base 36further includes radially outward spaced apart apertures 54. The spacedapart apertures 54 allow air to vent into the lubrication cavity of thewheel end to inhibit the creation of a vacuum as the bearings andlubrication cool during periods of non-use.

A valve 56 resides in the central aperture 52. The valve 56 is anelastic member and typically formed of an elastomeric. The valve 56 isfurther described in U.S. Pat. No. 5,860,708, issued Jan. 19, 1999,which is owned by Stemco, the disclosure of which is incorporated hereinby reference as if set out in full. Generally, the valve 56 is designedsuch that the vent is normally closed until the pressure in the wheelend increases due to operation (or other reasons). When pressure exceedsa set point, the valve opens to allow pressure to vent.

The base 36 is coupled to the vent plug body 58. The vent plug body 58extends in an inboard direction from the base 36 forming a generallycylindrical, hollow cavity 60. The vent plug body 58 defines an innerdiameter D3 although the vent plug body 58 may be cylindrical orfrustoconical as shown. The outer surface 62 of the vent plug body 58forms one or more annular glands 64, of which two annular glands 64 areshown. Seals 66, such as o-rings, form a seal between the vent plug 32and the hub cap 10, more specifically, the sight glass 22. The annularglands 64 are generally formed with a portion of the vent plug body 58forming the base of the annular gland 64 and one or more radiallyextending, annular ribs 68 forming walls of the annular gland 64.

A shield 70 is coupled to the inboard side 72 of the vent plug body 58,which is distal to the base 36. The shield 70, as shown in FIG. 2, has aradially extending disc body 74 and an axially extending connector ring76 with a radially extending annular connecting surface 78. The discbody 74 has a shape to cooperatively work with the shape of the ventplug body 59. The radially extending annular connecting surface 78 hasone or more bores 80. The radially extending disc body 74 has a diameterD4 slightly less than the corresponding diameter D3 of the vent plugbody 58. FIG. 3 shows a perspective view of the vent shield 70. The discbody 74 and the connector ring 76 are generally solid to inhibitlubricant from traversing from the lubrication cavity of the wheel endassembly to the cavity 60 of the vent plug 32. The connector ring 76 mayhave cutouts 77 to facilitate a gas vent path.

With reference back to FIG. 2 and FIG. 6, the inboard side 72 of thevent plug body 58 provides connector protrusions 82. The connectorprotrusions 82 have an axially extending leg 84 and a radially extendingledge 86. The connector protrusions 82 align with the bores 80 inconnecting surface 78. The terminal end 88 of the connector protrusions82 may be tapered or chamfered to facilitate inserting the connectorprotrusions 82 into the bores 80. Once the ledge 86 clears the bore 80,the elastic connector protrusion 82 moves the ledge 86 to engage theunderside 90 of the connecting surface 78 forming a snap fit connectionin this exemplary embodiment. While a snap fit connection is shown inthis exemplary embodiment as a means for connecting the shield to thevent plug body, the connection between the shield 70 and the vent plugbody 58 may be formed by alternative means, such as, for example, afriction fitting, adhesive, glues, welds 205, or the like. Moreover, theshield may be molded 205 with the vent plug body to form a monolithicpiece.

As can be appreciated, the shield 70 connection to the vent plug body 58provides a leak path for gas (air) from the inboard wheel end to thevent plug body 58, and eventually to atmosphere through interface 38.

FIG. 4 shows an alternative version of the shield 70′. Shield 70′ has aradially extending disc portion 74′ and a radially extending annularconnector surface 78′ extending from an edge 73′ of the disc portion74′. The connector surface 78′ may include bores 80′ to receive theconnector protrusions 82. The shield 70′ includes vent channels 92′ tofacilitate air flow. The vent channels 92′ may be incorporated intoother shields described herein.

FIGS. 5A-D5 show alternative vent plugs 94, 96, 98, and 100 with ashield 102, 104, 106, and 108. As shown, vent plugs 94, 96, and 98provide a valve 56 but as shown by vent plug 100, a valve 56 is not anecessary component of the vent plug. The shields 70, 70′, 102, 104,106, and 108 inhibit the flow of lubricant into the vent plug body 58.The shield 102 includes an axially extending central member 110 thatengages with the valve 56.

FIGS. 7A and 7B show a vent plug 120 with a shield 122 and a vent plug124 with a shield 126. Placement of the shield 122 inside the vent plugbody is shown towards the middle or outboard end 128 of the vent plug120. The specific placement of the shield 122 may vary depending on thecharacteristics and/or material of the vent plug 120. Placement ofshield 126 in vent plug 124 is toward the inboard end 130. In otherwords, the placement of the various shields described herein may beoptimized for the particular construction of the vent plug.

FIG. 8 shows a detail of means for connecting the vent plug body to theshield. A portion of a vent plug body 132 is shown. The vent plug body132 terminates, at the inboard side 134, with a shoulder 136. Theshoulder 136 is formed by a radially extending annular surface 138 andan axially extending annular rim 140. The shield 142 has a radiallyextending annular ledge 144 that mates with the shoulder 136 and forms ajunction 139. The shield 142 is coupled, in this exemplary embodiment,to the vent plug body 132 by a weld at points along junction 138.

FIG. 9 provides an alternative construction of a vent plug 200 with ashield 202. The vent plug 200 includes a cover 204 and a base 206. Thecover 204 and base 206 would have annular concentric rings as describedabove, but not shown here, to provide a labyrinth seal. The vent plug200 includes a valve 208, which is similar to the valve 56 describedabove.

The vent plug 200 further includes an annular vent plug body 210extending in an inboard direction from the base 206. The vent plug body210 includes one or more annular glands 212, which are formed in part byan outer surface 214 of the vent plug body 210 and radially extending,annular rib 216. The shield 202 traverses the space 218 defined by thevent plug body 210. The shield 202 has perforations 220 that provide avent path from the wheel end lubrication cavity to the space 218. Whilethe shield 202 may be a disc that traverses the space 218, the exemplaryshield 202 shown provides a central member 222 extending in an axial,outboard direction. The central member 222 is shown as a cylindricalmember with a distal protrusion 224 that is sized to fit within a bore226 of the valve 208. The central member 222 and protrusion 224 fittingwithin the bore 226 of the valve 208 provides for support among otherthings from the shield 202.

The vent plugs with shields, as described herein, generally provide aliquid barrier and a gas vent path. FIG. 10 shows an exemplary vent pathA for a vent plug 32 having a shield 70. FIG. 11 shows an exemplary ventpath B for a vent plug 32 having a shield 70′.

Although the technology has been described in language that is specificto certain structures and materials, it is to be understood that theinvention defined in the appended claims is not necessarily limited tothe specific structures and materials described. Rather, the specificaspects are described as forms of implementing the claimed invention.Because many embodiments of the invention can be practiced withoutdeparting from the spirit and scope of the invention, the inventionresides in the claims hereinafter appended. Unless otherwise indicated,all numbers or expressions, such as those expressing dimensions,physical characteristics, etc. used in the specification (other than theclaims) are understood as modified in all instances by the term“approximately.” At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the claims, each numericalparameter recited in the specification or claims which is modified bythe term “approximately” should at least be construed in light of thenumber of recited significant digits and by applying ordinary roundingtechniques. Moreover, all ranges disclosed herein are to be understoodto encompass and provide support for claims that recite any and allsubranges or any and all individual values subsumed therein. Forexample, a stated range of 1 to 10 should be considered to include andprovide support for claims that recite any and all subranges orindividual values that are between and/or inclusive of the minimum valueof 1 and the maximum value of 10; that is, all subranges beginning witha minimum value of 1 or more and ending with a maximum value of 10 orless (e.g., 5.5 to 10, 2.34 to 3.56, and so forth) or any values from 1to 10 (e.g., 3, 5.8, 9.9994, and so forth).

What is claimed is:
 1. A vent plug for a hub cap comprising, a cover; abase coupled to the cover and defining an interface, the base beinginboard of the cover; a chamber between and defined by the cover and thebase; an annular vent plug body extending in an inboard direction fromthe base where the base and the annular vent plug body define a hollowcavity; a shield coupled to the vent plug body and inboard of the base,the shield generally traversing the hollow cavity defined by the annularvent plug body, wherein a vent path configured to place a lubricationcavity of a wheel end assembly in fluid communication with the hollowcavity that inhibits liquid leaking between the wheel end assembly andthe hollow cavity of the vent plug.
 2. The vent plug of claim 1 whereinthe shield comprises a radially extending disc body.
 3. The vent plug ofclaim 2 wherein the vent path comprises a bore located in the radiallyextending disc body.
 4. The vent plug of claim 2 wherein the shieldcomprises an axially extending connector ring.
 5. The vent plug of claim4 wherein the connector ring comprises an annular connecting surfacehaving at least one bore.
 6. The vent plug of claim 5 wherein the ventplug body comprises at least one connector protrusion shaped to form aconnection with the at least one bore.
 7. The vent plug of claim 6wherein the at least one connector protrusion comprises an elastic legand a radially extending ledge to engage the underside of the annularconnecting surface.
 8. The vent plug of claim 2 wherein the radiallyextending disc body comprises vent channels.
 9. A vent plug for a hubcap comprising, a base; a vent plug body that defines a cavity, the ventplug body having an outboard side proximal the base and an inboard sidedistal the base; a shield comprising at least a radially extending disccoupled to the vent plug body and inboard of the base, the shieldgenerally traversing the cavity defined by the vent plug body, whereinthe shield comprises at least one bore and wherein the inboard side ofthe vent plug body comprises at least one connector protrusionconfigured to engage the at least one bore; and a vent path configuredto place a lubrication cavity of a wheel end assembly in fluidcommunication with the cavity of the vent plug and an atmosphere,wherein the vent path is configured to allow gas to vent from thelubrication cavity to the cavity and through the base to atmosphere andconfigured to inhibit liquid leaking between the lubrication cavity andthe cavity of the vent plug.
 10. The vent plug of claim 9 comprising atleast one aperture in the base and a valve retained in the at least oneaperture of the base and configured such that the valve is in fluidcommunication with the cavity.
 11. The vent plug of claim 10 wherein thevalve is configured to open when the cavity exceeds a pressure thresholdto place the cavity in gaseous fluid communication with the atmosphere.12. The vent plug of claim 9 wherein the radially extending disccomprising a plurality of vent channels.
 13. A vent plug for a hub capcomprising: a cover; a base, wherein the cover is outboard of andcoupled to the base; a vent plug body that defines a cavity, the ventplug body having an outboard side proximal the base and an inboard sidedistal the base; a shield comprising at least a radially extending disccoupled to the vent plug body and inboard of the base, the shieldgenerally traversing the cavity defined by the vent plug body; and avent path configured to place a lubrication cavity of a wheel endassembly in fluid communication with the cavity of the vent plug and anatmosphere, wherein the vent path is configured to allow gas to ventfrom the lubrication cavity to the cavity and through the base toatmosphere and configured to inhibit liquid leaking between thelubrication cavity and the cavity of the vent plug.
 14. The vent plug ofclaim 13 where the cover and the base define a chamber.
 15. The ventplug of claim 14 wherein the cover comprises a plurality of cover ribsextending from the cover towards the base and the base defines aplurality of base ribs extending from the base towards the cover whereinthe plurality of cover ribs are offset from the plurality of base ribssuch that the vent path is defined in part by a labyrinth path throughthe plurality of cover ribs and the plurality of base ribs in thechamber.